Characteristics of Closed-Cycle Micro Gas-Turbine Engines in Power Plants of Underwater Technics in Variable Modes

Underwater technics is especially required at the operation in the Arctic shelf and for equipping the facilities located along the Northern Sea Route with underwater vessels. This is explained by the necessity to pass through ice fields. Of the various power plant types, the most interesting one is the so-called closed-cycle micro gas-turbine plants (CMGTP), being able to use a single loop, operate with hydrocarbon fuel and use air as an oxidant. In this case there is no need in special onshore infrastructure limiting the cruising range of underwater technics. The turbine engine (GTE) with warmth regeneration is taken as a baseline CMGTP design. In addition, the authors consider CMGTP with a turbocompressor utilizer (TCU) and heat regeneration (R) as more cost-effective and having specific power 1.3...1.5 times higher than CMGTP with R. Also, one should obtain the CMGTP characteristics in variable modes as underwater technics is used for research, production and transportation under partial loads and various loading types. The research of CMGTP working cycles in variable modes are conducted with a new fluid - a mixture of nitrogen gases and hydrocarbon fuel combustion products. It is established that at any values of relative capacity the cost-effectiveness in the design with CMGTP with TCU and R is higher than in CMGTP with R at all loading types. At the screw loading the cost-effectiveness of all designs is higher than under the generator loading. The gas cooler after the recuperator in CMGTP can be used as a boiler-utilizer for general vessel purposes thus providing for a high plant energy efficiency.